CHAPTER V. 



MILK BACTERIA AND HEALTH. 



IT has been long recognized that poor milk is a source of 

 a considerable amount of sickness, especially among children. 

 It was the poor quality of the milk from a chemical stand- 

 point that was at first regarded as responsible for most of the 

 sickness resulting from its use. If milk is highly adulter- 

 ated so as to contain only a small quantity of food products, 

 or adulterated with materials that are themselves injurious, 

 the milk becomes unwholesome; and it has generally been 

 believed that such causes have been at the bottom of much 

 of the sickness that results from use of milk. The develop- 

 ment of the system of milk inspection and the setting of a 

 chemical standard which milk must reach to be sold on the 

 market, has raised the chemical purity of market milk, so that, 

 speaking in broad terms, it may be said that against the 

 adulterations of milk by water or chemicals the public is, on 

 the whole, quite .well protected. 



It has been a growing belief in the last ten years that the 

 larger portion of the sickness that comes from the use of 

 bad milk is attributable, not to adulteration or chemical 

 impurities, but to the bacteria present in the milk. We 

 have already noticed how numerous these bacteria some- 

 times are in city milk, and the recognition of the fact that 

 many diseases are caused by bacteria has led to the belief 

 that milk bacteria are the cause of much of the sickness 

 attributable to milk. The ground for this belief is more than 

 a simple inference, since with quite a number of diseases the 

 direct connection between the disease and the bacteria in the 

 milk has been traced. 



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